Ableton is for composing music and for playback in a live situation...hence its name
its main attraction, or difference is the fact that it has two views...one is a for playing back events, or loops, in a live mix...also a great tool for sketches or seeing if sounds work together
the second view is like any traditional DAW....with arranged recordings running from left to right
its ideal for beat making and has some great features...highlights would be its sampler, drum racks, and audio warping...also some FX are geared towards electronic styles such as beat repeat and its built in arpeggiator
bear in mind its not beginner friendly and takes a bit of investment...but put it this way, I have sonar studio, and installed Logic9, thats all I did, installed it because its ableton that gets opened first everytime